a stack of thin, flat crystals that form a "book", e.g. book of mica

means angular, refers to a type of rock where angular pieces of rocks are “cemented” together with fine grained sand, type of sedimentary rock

a small cluster or plate of crystals, e.g. amethyst button

a unit of weight for gems. A carat is one fifth of a gram (0.2g). (GS)

spherical mass that is separate from the rock around it, usually weathers out of host rock, grows from the inside out

the form that the crystals of a mineral take when they have enough space and time to grow properly

branching, tree-like growths

very dull, mainly in minerals that are porous

used to describe mineral crystals that are long and thin and look like fibers

fully formed or doubly-terminated crystals that are unattached to other crystals